Firefox only (Win/Mac/Linux): Firefox extension CommentBlocker hides comments on most websites by default, allowing you to toggle them visible only when you want to see them.

Once you've installed the extension, almost any website with comments will be automatically hidden and an icon will show up in your location bar that lets you toggle the comments on for that session, or add the current site to the trusted list and always show comments.

It's a useful extension that might help declutter your daily reading, and since you can add sites to the trusted list, you can still participate in the comments on your favorite sites—like here at Lifehacker. CommentBlocker is a free download, works anywhere Firefox extensions do.